5G communication operates in a multi-band frequency range from approximately 18.5 GHz to 41.5 GHz. A multi-band frequency operation requires a PLL which can operate in two or more frequency bands (e.g., 18.5 GHz to 26.5 GHz, 31.5 GHz to 41.5 GHz, etc.) in the wireless transceiver communication devices. Conventional 5G communication PLLs may directly assemble several narrow-band PLLs on a single integrated circuit (IC) chip or on a multi-chip module (MCM) to operate at multiple frequency bands. However, this approach suffers from a high cost due to excessive chip/module area.
An alternative approach is to use higher order harmonic frequencies (e.g., second, third, fourth harmonic frequencies) as the output signals. This approach, although reduces the number of PLLs in the wide-bandwidth 5G communication systems, however, require additional filters and amplifiers to select the higher order harmonics and to amplify the higher order harmonic signals to provide a desirable power output to drive subsequent stages of the circuit. Furthermore, higher order harmonic signals have frequencies limited to some multiples of the first harmonic frequency.